Understanding Voltages in a circuit

Discussion in 'General Electronics Chat' started by Abhinavrajan, Sep 5, 2016.

  1. Abhinavrajan

    Thread Starter Member

    Aug 7, 2016
    81
    1
    Please look at the simple circuit and help me understand the concept of voltage.

    1. Assume the circuit is in open condition. What would the voltage between point B and ground ? - Please answer this and help me understand a bit more clearly.


    2. Assume the circuit is closed and current flows through it.

    2a. What would be the value of voltage between point A and ground ?
    2b. What would be the value of voltage between point B and ground ?

    Please explain with some reason and in simple english. An example or analogy for the answers would be really great. Thanks.
     
  2. R!f@@

    AAC Fanatic!

    Apr 2, 2009
    9,618
    1,088
    With Switch closed.
    A is across the battery so A to GND has Battery Voltage.
    B is same as ground. So No voltage

    And Switch open.
    A and B has same voltage respective to GND as battery since no current is flowing through circuit.
     
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  3. AlbertHall

    Distinguished Member

    Jun 4, 2014
    4,222
    959
    1. With the switch open the voltage at both A & B will be 10V. A is simply the battery voltage. There is no current flowing so the voltage across the resistor is zero (V = I * R) and therefore the voltage at B is the same as A, 10V.
    2a. The voltage at A is unchanged. It is the voltage across the battery.
    2b. With the switch closed, B is connected directly to ground so there is zero voltage between B and ground. The difference between A & B is now equal to the battery voltage.
    A the voltage at A
    B the voltage at B
    V voltage across the resistor
    I current through the resistor
    R the value of the resistor
    V = I * R
    I = V / R
    I = (A - B) / R
    I = (10V - 0V) / 10Ω
    I = 10V / 10Ω
    I = 1 amp.
     
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  4. Abhinavrajan

    Thread Starter Member

    Aug 7, 2016
    81
    1
    Thank you! :)
     
  5. Abhinavrajan

    Thread Starter Member

    Aug 7, 2016
    81
    1
    Thank you! :)
     
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